Hydrogen sulfide counteracts chlorophyll loss in sweetpotato seedling leaves and alleviates oxidative damage against osmotic stress |
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Authors: | Hua Zhang Yong-Kang Ye Song-Hua Wang Jian-Ping Luo Jun Tang Dai-Fu Ma |
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Institution: | (1) Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA;(2) Everglades Division, South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, FL 33406, USA |
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Abstract: | Sawgrass (Cladium jamaicense) is the predominant plant and vegetation community in the Florida Everglades. Germination of sawgrass seeds in the laboratory
or nursery has been difficult and problematic, yet little is known about the physiological mechanistic regulation of the sawgrass
seed germination process. In the present study, we examined the factors and mechanisms that influence sawgrass seed germination.
We found that removal of seed husk and bracts, pre-soaking with bleach (hypochlorite), breaking the seed coat, or combinations
of these treatments promoted the rate and success of germination, whereas presence of seed-encasing structures or treatment
with husk/bract extract inhibited germination. We further detected the presence of abscisic acid (ABA) in the husk and bract.
Experiments with ABA and gibberellin biosynthesis inhibitors fluridone and tetcyclacis suggested that ABA already presented
in the pre-imbibed seeds, and not derived through post-dormancy de novo synthesis, contributed to the inhibition of seed germination.
Examination of bleach and mechanical treatments indicated the physical barrier presented by the seed-encasing structures provided
additional mechanism for the long-term delay of seed germination. Based on the results of this study and others, we discussed
the implications of sawgrass seed dormancy and germination in relation to its natural habitat and proposed a hypothesis that
the protracted seed dormancy in sawgrass offered an adaptive advantage in the pre-anthropogenic Everglades environment, but
may become a liability in the current man-managed Everglades water system. |
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Keywords: | Sawgrass (Cladium jamaicense) Cattail (Typha domingensis) Husks/bracts Seed germination Abscisic acid (ABA) Gibberellins Wetland plant Florida Everglades |
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